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The uBeam FAQ
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sdpkom:

--- Quote from: Marco on January 24, 2019, 01:37:51 pm ---
--- Quote from: sdpkom on January 22, 2019, 07:06:14 am ---its the famous engineering situation - pick any two

--- End quote ---

There's also the Disney solution ... make the entire room a Faraday cage and use a big high intensity but low frequency emitter.

--- End quote ---

I believe for the people inside the room, this one is not safe, and does interfere with other devices in the room (e.g. not FCC compatible inside)
although it probably is OK with FCC from the outside.

___________________________________________________
Outside of a dog, a book is a man's best friend. Inside of a dog it's too dark to read. Groucho Marx
Outside the room its FCC compatible, Inside the room it's too dangerous to ..... read.
Marco:

--- Quote from: sdpkom on January 24, 2019, 02:56:47 pm ---I believe for the people inside the room, this one is not safe

--- End quote ---
Not much less safe than having an inductive charging cradle on your nightstand. Same kind of frequencies, same kind of field strengths near the emitter ... it's just that what's near changes with the size of it.
sdpkom:

--- Quote from: Marco on January 24, 2019, 03:29:52 pm ---
--- Quote from: sdpkom on January 24, 2019, 02:56:47 pm ---I believe for the people inside the room, this one is not safe

--- End quote ---
Not much less safe than having an inductive charging cradle on your nightstand. Same kind of frequencies, same kind of field strengths near the emitter ... it's just that what's near changes with the size of it.

--- End quote ---

A Qi charging cradle has two modes of operation.

When no receiver is placed on it - it turns off and emits no radiation (almost).
When you place something on it, it has a few safety systems to detect if it's a real receiver. It will not turn on unless it is a good receiver placed correctly.
The receiver absorbs most of the radiation, so that it's not emitted to the surrounding.

There is also the fact you don't usually sit on your charging cradle.
drussell:

--- Quote from: PaulReynolds on January 24, 2019, 08:07:44 am ---Those who held the next generation transducers seemed to think them roughly the same lateral dimensions as the Muratas, perhaps a bit thinner, but nowhere close to the "4x smaller area, 100x thinner" listed in the Oct 17 fundraising. They did say that the demo was being done with COTS devices.
--- End quote ---

That is just as I suspected.  STILL, at this point, how many years and millions of dollars later, all they have to show for their efforts is more cobbled together attempts at a proof-of-concept demonstration using commercially available parts.  Attempts to demonstrate a system which is a fundamentally flawed concept.

But what do we know?  We're engineer-types.  We just don't believe hard enough.  :palm:
PaulReynolds:

--- Quote from: coppice on January 24, 2019, 09:21:11 am ---Wouldn't they still need an electronically steered beam to get the responsiveness they need? The target can be quite agile.

--- End quote ---

If you were charging a phone in use, yes. If you have pivoted to "IoT" which are almost all fixed location devices, no.

If they are using the motorized stage to do the targetting, then essentially the phased array becomes a variable depth focus bowl and that's all you use it for. Drastically simplifies the electronics and beamforming, you just connect the transducers into concentric rings and you move from N^2 connections to N/2 (approx), so a reduction of roughly a factor of 2N, where N is the number of elements across the transmitter. uBeam transmitter I've seen publicly show an estimated 16 to 45 elements across.
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